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| From | Randy Yates <randyy@garnerundergroundinc.com> |
|---|---|
| Newsgroups | comp.dsp |
| Subject | Re: How to downsample this signal? |
| Organization | Garner Underground, Inc. |
| References | (2 earlier) <ofamgn$bbs$1@node1.news.atman.pl> <ofbbkq$mit$1@dont-email.me> <ofbdtb$vg$1@node1.news.atman.pl> <ofcf3l$6o8$1@dont-email.me> <87h90mqfwv.fsf@garnerundergroundinc.com> |
| Date | 2017-05-15 17:20 -0400 |
| Message-ID | <878tlxrf49.fsf@garnerundergroundinc.com> (permalink) |
Randy Yates <randyy@garnerundergroundinc.com> writes: > rickman <gnuarm@gmail.com> writes: > >> On 5/15/2017 1:21 AM, Piotr Wyderski wrote: >>> rickman wrote: >>> >>>> Are the 248 words for data or also program? >>> >>> Data only, there are dedicated code memories. The control part >>> is totally crazy: there are two separate code memories working >>> in parallel (they take both paths simultaneosly in order to >>> provide instructions with no delay in the case of a branch). >>> But there is no such thing as a program counter, the code >>> memories store instructions at consecutive addresses without >>> any deeper structure. A run of instructions is called a block >>> and is ended with the presence of a jump instruction. There >>> is also a third control memory which stores the information >>> where the i-th block begins and to which j-th state the FSM >>> should go in the case of a branch. In short, hardware basic >>> blocks. The data path is a VLIW with exposed pipelining, >>> which adds fun. >>> >>>> That should be plenty of room for coefficients. >>> >>> But doesn't the FIR require a lot of cells for >>> the past data values? >> >> Like I said, I wrote this a long time ago, so I am not the resource to >> be asking. I can't picture how it works, but I specifically remember >> NOT needing to store previous data inputs. I am thinking you store >> outputs which will be fewer because of the decimation. As the input >> data comes in the output samples can be built up and when one is >> complete it is outputted and replaced by a new one. >> >> But read a proper reference. If I wasn't busy today I'd dig this up >> for you. > > Yes you do need to store N-1 previous inputs (plus 1 current input) for > a length N polyphase FIR decimation by M. Just think first principles: > for any output y[k], you need N inputs to compute it, even if k = n*M. Correction: even if n = k*M, or k = floor(n/M). > > However, you don't have to input and shift every input as you do for a > normal-rate FIR. -- Randy Yates, Embedded Firmware Developer Garner Underground, Inc. 866-260-9040, x3901 http://www.garnerundergroundinc.com
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How to downsample this signal? Piotr Wyderski <peter.pan@neverland.mil> - 2017-05-13 09:23 +0200
Re: How to downsample this signal? Evgeny Filatov <filatov.ev@mipt.ru> - 2017-05-13 15:42 +0300
Re: How to downsample this signal? bitterlemon40@yahoo.ie - 2017-05-13 07:53 -0700
Re: How to downsample this signal? rickman <gnuarm@gmail.com> - 2017-05-13 11:48 -0400
Re: How to downsample this signal? Randy Yates <yates@digitalsignallabs.com> - 2017-05-13 12:58 -0400
Re: How to downsample this signal? rickman <gnuarm@gmail.com> - 2017-05-13 16:04 -0400
Re: How to downsample this signal? Randy Yates <yates@digitalsignallabs.com> - 2017-05-14 14:19 -0400
Re: How to downsample this signal? Piotr Wyderski <peter.pan@neverland.mil> - 2017-05-15 00:42 +0200
Re: How to downsample this signal? rickman <gnuarm@gmail.com> - 2017-05-15 00:46 -0400
Re: How to downsample this signal? Piotr Wyderski <peter.pan@neverland.mil> - 2017-05-15 07:21 +0200
Re: How to downsample this signal? rickman <gnuarm@gmail.com> - 2017-05-15 10:51 -0400
Re: How to downsample this signal? Randy Yates <randyy@garnerundergroundinc.com> - 2017-05-15 11:49 -0400
Re: How to downsample this signal? Randy Yates <randyy@garnerundergroundinc.com> - 2017-05-15 17:20 -0400
Re: How to downsample this signal? rickman <gnuarm@gmail.com> - 2017-05-16 02:59 -0400
Re: How to downsample this signal? eric.jacobsen@ieee.org - 2017-05-16 15:59 +0000
Re: How to downsample this signal? rickman <gnuarm@gmail.com> - 2017-05-16 15:36 -0400
Re: How to downsample this signal? Randy Yates <randyy@garnerundergroundinc.com> - 2017-05-16 13:11 -0400
Re: How to downsample this signal? eric.jacobsen@ieee.org - 2017-05-16 18:08 +0000
Re: How to downsample this signal? Randy Yates <randyy@garnerundergroundinc.com> - 2017-05-16 15:35 -0400
Re: How to downsample this signal? Randy Yates <randyy@garnerundergroundinc.com> - 2017-05-16 15:45 -0400
Re: How to downsample this signal? Randy Yates <randyy@garnerundergroundinc.com> - 2017-05-16 15:50 -0400
Re: How to downsample this signal? rickman <gnuarm@gmail.com> - 2017-05-16 21:36 -0400
Re: How to downsample this signal? rickman <gnuarm@gmail.com> - 2017-05-16 15:35 -0400
Re: How to downsample this signal? Randy Yates <randyy@garnerundergroundinc.com> - 2017-05-16 15:36 -0400
Re: How to downsample this signal? Randy Yates <randyy@garnerundergroundinc.com> - 2017-05-16 15:40 -0400
Re: How to downsample this signal? rickman <gnuarm@gmail.com> - 2017-05-16 22:06 -0400
Re: How to downsample this signal? Randy Yates <yates@digitalsignallabs.com> - 2017-05-17 01:25 -0400
Re: How to downsample this signal? Evgeny Filatov <filatov.ev@mipt.ru> - 2017-05-15 14:51 +0300
Re: How to downsample this signal? Randy Yates <randyy@garnerundergroundinc.com> - 2017-05-15 10:37 -0400
Re: How to downsample this signal? makolber@yahoo.com - 2017-05-15 06:27 -0700
Re: How to downsample this signal? Piotr Wyderski <peter.pan@neverland.mil> - 2017-05-15 20:39 +0200
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